We do not possess the advantage (which we have in the case of Aristotle) of knowing this quadruple scheme as stated and enforced by its authors. We know it only through the abridgment of Diogenes Laertius, together with incidental remarks and criticisms, chiefly adverse, by Plutarch, Sextus Empiricus, Plotinus, and some Aristotelian commentators. As far as we can make out upon this evidence, it appears that the first Stoic Category corresponded with the [Greek: Prô/tê Ou)si/a], First Essence or Substance of Aristotle. It was exclusively Subject, and could never become Predicate; but it was indispensable as Subject, to the three other Predicates. Its meaning was concrete and particular; for we are told that all general notions or conceptions were excluded by the Stoics from this Category,[132] and were designated as [Greek: Ou)/tina], Non-Individuals, or Non-Particulars. _Homo_ was counted by them, not under the Category [Greek: ti/], _Quid_, but under the Category [Greek: _poio/n_], _Quale_; in its character of predicate determining the Subject [Greek: ti/s] or [Greek: ti/]. The Stoic Category _Quale_ thus included the Aristotelian Second Essences or Substances, and also the Aristotelian _differentia_. _Quale_ was a _species_-making Category ([Greek: ei)dopoio/s]).[133] It declared what was the Essence of the Subject [Greek: ti/]--the essential qualities or attributes, but also the derivative manifestations thereof, coinciding with what is called the _proprium_ in Porphyry's Eisagoge. It therefore came next in order immediately after [Greek: ti/]: since the Essence of the Subject must be declared, before you proceed to declare its Accidents. [Footnote 132: Simpl. ad Categ., p. 54, a. 12, Schol. Brand.: [Greek: sumparalêpte/on de\ kai\ tê\n sunê/theian tô=n Stôi+kô=n peri\ tô=n genikô=n poiô=n, pô=s ai( ptô/seis kat' au)tou\s prophe/rontai, kai\ pô=s _ou)/tina_ ta\ koina\ par' au)toi=s le/getai, kai\ o(/pôs para\ tê\n a)/gnoian tou= mê\ pa=san ou)si/an to/de ti sêmai/nein kai\ to\ _para\ to\n ou)/tina_ so/phisma gi/netai para\ to\ schê=ma tê=s le/xeôs; oi(=on ei)/ ti/s e)stin e)n A)thê/nais, ou)k e)/stin e)n Mega/rois; _ o( ga\r a)/nthrôpos ou)/tis e)sti/n, ou) ga/r e)sti/ tis o( koino/s_, ô(s tina\ de\ au)to\n e)la/bomen e)n tô=| lo/gô|, kai\ para\ tou=to to\ o)/noma tou=to e)/schen o( lo/gos ou)/tis klêthei/s.] Compare Schol. p. 45**, a. 7, where Porphyry says that the Stoics, as well as Aristotle, in arranging Categories, took as their point of departure [Greek: to\ **deu/teron u(pokei/menon], not [Greek: to\ prô=ton u(pokei/menon ( = tê\n a)/poion u(/lên)].]